Photosensitive material and method of lithography

ABSTRACT

Methods and materials directed to a photosensitive material and a method of performing a lithography process using the photosensitive material are described. A semiconductor substrate is provided. A layer including an additive component is formed over the semiconductor substrate. The additive component includes a metal cation. One or more bonds are formed to bond the metal cation and one or more anions. Each of the one or more anions is one of a protecting group and a polymer chain bonding component. The polymer chain bonding component is bonded to a polymer chain of the layer. The layer is exposed to a radiation beam.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Application No.62/265,869, filed Dec. 10, 2015, entitled “PHOTOSENSITIVE MATERIAL ANDMETHOD OF LITHOGRAPY,” the entire disclosure of which is incorporatedherein by reference.

BACKGROUND

The semiconductor integrated circuit (IC) industry has experienced rapidgrowth. Technological advances in IC materials and design have producedgenerations of ICs where each generation has smaller and more complexcircuits than the previous generation. However, these advances haveincreased the complexity of processing and manufacturing ICs and, forthese advances to be realized, similar developments in IC processing andmanufacturing are needed. In the course of IC evolution, functionaldensity (i.e., the number of interconnected devices per chip area) hasgenerally increased while geometry size (i.e., the smallest componentthat can be created using a fabrication process) has decreased.

As the semiconductor device sizes continue to shrink, for example below20 nanometer (nm) nodes, traditional lithography technologies haveoptical restrictions, which leads to resolution issues and may notachieve the desired lithography performance. In comparison, extremeultraviolet (EUV) lithography can achieve much smaller device sizes.However, EUV lithography still has some shortcomings related tophotoresist, for example shortcomings with respect to sensitivity and/orefficiency. As a result, lithography performance may be compromised ordegraded.

Thus, a process and material that reduces, minimizes, or removesproblems with a patterning material is desired.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read in association with the accompanyingfigures. It is noted that, in accordance with the standard practice inthe industry, various features in the drawings are not drawn to scale.In fact, the dimensions of illustrated features may be arbitrarilyincreased or decreased for clarity of discussion.

FIG. 1 is a flowchart of an embodiment of a method for making asemiconductor device according to various aspects of the presentdisclosure.

FIG. 2 is a flowchart of an embodiment of a method for forming apatterning layer according to various aspects of the present disclosure.

FIG. 3 is a flowchart of an embodiment of a method for forming apatterning layer according to various aspects of the present disclosure.

FIG. 4A is a flowchart of an embodiment of a method for forming apatterning layer according to various aspects of the present disclosure.FIG. 4B is a flowchart of an embodiment of a method for forming apatterning layer according to various aspects of the present disclosure.FIG. 4C is a flowchart of an embodiment of a method for forming apatterning layer according to various aspects of the present disclosure.FIG. 4D is a flowchart of an embodiment of a method for making asemiconductor device according to various aspects of the presentdisclosure.

FIGS. 5A, 5B, 6, 7, 8, and 9 are diagrammatic fragmentarycross-sectional side views of an embodiment of a semiconductor deviceaccording to various aspects of the present disclosure.

FIGS. 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10I, 10J, 10K, 11A, 11B,11C, and 11D illustrate embodiments of an additive component accordingto various aspects of the present disclosure.

FIGS. 12A, 12B, and 12C are diagrammatic fragmentary cross-sectionalside views of an embodiment of a semiconductor device according tovarious aspects of the present disclosure. FIG. 12D illustrates anembodiment of a floating additive material according to various aspectsof the present disclosure.

FIGS. 13, 14, 15A, 15B, 15C, 15D, and 16 are diagrammatic fragmentarycross-sectional side views of an embodiment of a semiconductor deviceaccording to various aspects of the present disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Extreme ultraviolet (EUV) lithography has become widely used due to itsability to achieve small semiconductor device sizes, for example for 20nanometer (nm) technology nodes or smaller. The EUV photolithographyprocess using a EUV light with a wavelength of about 13.5 nm. However,an acid generator in the photoresist may not absorb such alow-wavelength UV light. According to the acid generating mechanism ofthe EUV exposure, a sensitizer may be used in the EUV lithographyprocess. A sensitizer includes an element that absorbs the EUV light andgenerates secondary electrons. When the EUV light strikes thephotoresist, the sensitizer in the photoresist absorbs the EUV light andgenerates secondary electrons. These secondary electrons then react withthe acid generator to generate acid. Thereafter, the acid reacts withthe photoresist polymers changing the chemical properties of thephotoresist polymers. However, this process may suffer from poor acidgeneration sensitivity and efficiency due to weak EUV light absorptionof the main elements (e.g., carbon, oxygen, and hydrogen) of the polymerand the acid generator in the photoresist. The present disclosureenhances photoresist sensitivity and efficiency while balancingsensitivity, resolution, and line width roughness (LWR) by using asensitizer additive material having an element having higher EUV lightabsorption than the main elements of the photoresist.

FIG. 1 is a flowchart of an embodiment of a method 100 of making asemiconductor device 500 according to aspects of the present disclosure.FIGS. 2, 3, 4A, 4B, 4C, and 4D are flowcharts of various embodiments ofmethods of forming a patterning layer including sensitizer additivecomponents at block 104 of the method 100. It is understood that themethod 100 includes steps having features of a complementarymetal-oxide-semiconductor (CMOS) technology process flow and thus, areonly described briefly herein. Additional steps may be performed before,after, and/or during the method 100.

It is also understood that parts of the semiconductor device 500 may befabricated by complementary metal-oxide-semiconductor (CMOS) technologyprocess flow, and thus some processes are only briefly described herein.Further, the semiconductor device 500 may include various other devicesand features, such as additional transistors, bipolar junctiontransistors, resistors, capacitors, diodes, fuses, etc., but issimplified for a better understanding of the inventive concepts of thepresent disclosure.

The semiconductor device 500 may be an intermediate device fabricatedduring processing of an integrated circuit, or portion thereof, that maycomprise static random access memory (SRAM) and/or other logic circuits,passive components such as resistors, capacitors, and inductors, andactive components such as P-channel field effect transistors (PFET),N-channel FET (NFET), metal-oxide semiconductor field effect transistors(MOSFET), complementary metal-oxide semiconductor (CMOS) transistors,bipolar transistors, high voltage transistors, high frequencytransistors, other memory cells, and combinations thereof. Thesemiconductor device 500 may include a plurality of semiconductordevices (e.g., transistors), which may be interconnected.

The method 100 begins at block 102 providing a substrate including atarget layer. Referring to the example of FIG. 5A, a substrate 502 isillustrated. The substrate may be a semiconductor substrate, such as asemiconductor wafer. The substrate may include silicon in a crystallinestructure. In alternative embodiments, the substrate may includegermanium, silicon germanium, silicon carbide, gallium arsenide, indiumarsenide, indium phosphide, and/or other suitable materials. Thesubstrate may be a silicon-on-insulator (SOI) substrate.

In some embodiments, the substrate 502 is substantially conductive orsemi-conductive. The electrical resistance may be less than about 10³ohm-meter. In some embodiments, the substrate 502 contains metal, metalalloy, metal nitride, and/or metal/sulfide/selenide/oxide/silicide withthe formula MXa, where M is a metal, and X is N, S, Se, O, Si, and where“a” is in a range from about 0.4 to about 2.5. For example, thesubstrate 502 may contain Ti, Al, Co, Ru, TiN, WN₂, and/or TaN.

In some other embodiments, the substrate 502 contains a dielectricmaterial with a dielectric constant in a range from about 1 to about 40.In some other embodiments, the substrate 502 contains Si, metal oxide,or metal nitride, where the formula is MXb, wherein M is a metal or Si,and X is N or O, and wherein “b” is in a range from about 0.4 to about2.5. For example, the substrate 502 may contain SiO₂, silicon nitride,aluminum oxide, hafnium oxide, and/or lanthanum oxide.

In some embodiments, the substrate 502 may include a plurality of layersand/or features formed on the semiconductor substrate including dopedregions or wells, isolation regions such as shallow trench isolation(STI) features, conductive layers, insulating layers, and various othersuitable features. For example, the substrate may include one or moretarget layers, which are desired to patterned. In embodiments, thesubstrate 502 has any plurality of layers (conductive layer, insulatorlayer) or features (source/drain regions, gate structures, interconnectlines and vias), formed thereon. The substrate 502 may include one ormore target layers 504 disposed on a semiconductor substrate; the targetlayers 504 suitable for patterning by the method 100, and may bereferred to as patternable layers 504. Exemplary target layers includegate layers, interconnect layers, and/or other suitable layers. In someembodiments, the target layer 504 includes a dielectric material, suchas silicon oxide or silicon nitride. In some embodiments, the targetlayer 504 includes metal. In some embodiments, the target layer 504includes a semiconductor material. It is understood that the substrate502 and the target layer 504 may each include additional suitablematerial compositions in other embodiments.

In some embodiments, the patterning by the method 100 may be suitable toetch portions of the semiconductor substrate 502 itself (e.g., such asin the formation of fins for a fin-type field effect transistor).

Referring now to FIG. 1, the method 100 then proceeds to block 104,where a patterning layer including a sensitizer additive component maybe formed over the substrate. In various embodiments, when thepatterning layer 506 is exposed to a EUV light (e.g., during asubsequent EUV photolithography process using a EUV light having awavelength of about 13.5 nm), the sensitizer additive component in thepatterning layer 506 may absorb the EUV light and release secondaryelectrons, which then react with the PAG to generate acid. As such, thesensitizer additive component may be used to improve sensitivity of thepatterning layer 506. The sensitizer additive component is discussed indetail below with reference to FIGS. 2 and 10A-11D.

Referring to the example of FIG. 5A, a patterning layer 506 is disposedover the target layer 504. In some embodiments, the patterning layer 506may include one or more layers have different optical properties. Forexample, the patterning layer 506 may include a tri-layer stackincluding a bottom inorganic layer (also referred to as an underlayertri-layer stack), a middle anti-reflective coating layer (also referredto as a middle layer of the tri-layer stack), and a top photoresistlayer (also referred to as a photoresist layer of the tri-layer stack).In some examples, the various layers of the patterning layer 506 maycomprise substantially different refractive indexes (i.e., n values),extinction coefficients (i.e., k values), or thicknesses (T). In someembodiments, the various layers of the patterning layer 506 may furthercomprise different etching resistances and may contain at least oneetching resistant molecule. The etching resistant molecule may include alow onishi number structure, double bond, triple bond, silicon, siliconnitride, Ti, TiN, Al, aluminum oxide, SiON, or combinations thereof.

In the illustrated example of FIG. 5A, the patterning layer 506 includesa positive photoresist, but it is understood that the patterning layer506 may include a negative photoresist in alternative embodiments. Thepatterning layer 506 may contain components such as a polymer, photoacidgenerators (PAG), thermal acid generators (TAG), quenchers, chromophore,surfactant, cross linker, etc. In an embodiment, the PAG is bonded tothe polymer. In some embodiments, in a subsequent photolithographyprocess, photons induce decomposition of the PAG. As a result, a smallamount of acid is formed, which further induces a cascade of chemicaltransformations in the patterning layer 506. The patterning layer 506may also optionally include a quencher that is disposed within thepatterning layer 506 in order to improve critical dimension (CD)control.

Referring now to FIG. 5B, in some embodiments, at block 104, a topcoatlayer 508 may be formed over the patterning layer 506. In someembodiments, the sensitizer additive component in the patterning layer506 may be volatile and diffuse out of the patterning layer 506. Thetopcoat layer 508 may act as a diffusion barrier layer so that thesensitizer additive component remains in the patterning layer 506. Insome embodiments, the topcoat layer 508 may include a top antireflectivecoating (TARC), and/or other organic or inorganic coatings as known inthe art. The topcoat layer 508 may be formed by a spin-on coatingprocess, chemical vapor deposition process (CVD), physical vapordeposition (PVD) process, and/or other suitable deposition processes.

Referring now to FIG. 1, the method 100 then proceeds to block 106,where an exposure process is performed to expose the patterning layerthereby patterning the patterning layer. As discussed in detail below,the sensitizer additive components contained in the patterning layer 506may promote more efficient photo-acid generation, thereby enhancingphotoresist sensitivity and efficiency while balancing sensitivity,resolution, and line width roughness (LWR). The radiation beam mayexpose the resist deposited on the substrate using a lithography systemthat provides a pattern of the radiation according to an IC designlayout. In one embodiment, a lithography system includes an ultraviolet(UV) radiation, a deep ultraviolet (DUV) radiation, an extremeultraviolet (EUV) radiation, an X-ray radiation, and/or other suitableradiation types. In alternative embodiments, a lithography systemincludes a charged particle lithography system, such as an electron beamor an ion beam lithography system.

Referring now to the example of FIG. 6, a patterned radiation beam 602is incident on the substrate 502 and specifically the patterning layer506. The regions 506A illustrate the portions of the resist that havebeen exposed to the radiation, and thus, a chemical change has occurredin those regions. In the illustrated example of FIG. 6, the patterninglayer 506 includes positive resist, and the regions 506A become solublein developers. Alternatively, in the case of negative resist, theregions 506A are insoluble in developers.

In embodiments of the method 100, after the exposure process, a bakingprocess may occur. The bake may be a hard bake. In an embodiment, thepatterning layer 506 may include a chemically amplified resist (CAR),and the bake process serves to improve the insolubility of the CAR.

The method 100 then proceeds to block 108 where the exposed layer(s) aredeveloped to form a masking element. A developer may be applied to theexposed resist to form a resist pattern on the substrate. In anembodiment, a positive tone developer is applied in block 108. The term“positive tone developer” refers to a developer that selectivelydissolves and removes areas that received exposure dose (or an exposuredose above a predetermined threshold exposure dose value). In anembodiment, a negative tone developer is applied in block 108. The term“negative tone developer” refers to a developer that selectivelydissolves and removes areas that received no exposure dose (or anexposure dose below a predetermined threshold exposure dose value).

In an embodiment, a developer may include an organic solvent or amixture of organic solvents, such as methyl a-amyl ketone (MAK) or amixture involving the MAK. In another embodiment, a developer includes awater based developer, such as tetramethylammonium hydroxide (TMAH).Applying a developer includes spraying a developer on the exposedpatterning layer 506, for example by a spin-on process. In anembodiment, the developer may remove the exposed regions 506A of thepatterning layer 506.

Referring to the example of FIG. 7, a masking element 702 is provided inthe patterning layer 506. The masking element 702 may be formed byapplying a developer to the exposed patterning layer 506. In anembodiment, the masking element 702 is used to etch an underlying layer.In turn, the etched underlying layer may be used as a masking element topattern additional layers. In other embodiments or further embodiments,one or more of the layers on the substrate 502 may also be patternedusing subsequent etching processes such as dry etching or plasma etchingbased on the pattern provided by the masking elements 702.

Referring now to FIGS. 1 and 8, the method 100 then proceeds to block110, where the masking element is used to form a semiconductor devicefeature. In an embodiment, the masking element includes one or more oflayers (e.g., the photoresist layer, the middle layer, and/or theunderlayer) of the patterning layer 506. In a further embodiment, aphotoresist layer of the patterning layer 506 is stripped aftertransferring the pattern to a middle layer (by suitable etching processdiscussed above) of the patterning layer 506. The patterned middle layermay then be used as the masking element to pattern additional layer(s).Referring to the example of FIG. 8, features 802 are formed of thetarget layer 504 of the substrate 502. The features 802 are defined bythe masking element 702. Features 802 may be gate structures, finstructures such as provided in a fin-type field effect transistor,interconnect structures, isolation features, conductive features such aslines, and/or other suitable semiconductor device features.

The method 100 may continue with further steps not specificallydescribed herein but understood by one of ordinary skill in the art. Forexample, the semiconductor device 500 may next be subjected to a rinsingprocess, such as a de-ionized (DI) water rinse. The rinsing process mayremove residue particles.

Referring now to FIGS. 2, 9, 10A, 10B, 10C, 10D, 10E, 11A, 11B, 11C, and11D, illustrated is an exemplary embodiment of a method 200 of forming apatterning layer including a sensitizer additive component at block 104of the method 100. In some embodiments, the patterning layer may be atri-layer patterning layer including an underlayer, a middle layerdisposed over the underlayer, and a photoresist layer disposed over themiddle layer. In some embodiments, one or more of the underlayer, middlelayer, and photoresist layer may include sensitizer additive components,which may improve the sensitivity of the patterning layer.

Referring to FIG. 2 and the example of FIG. 9, the method 200 begins atblock 202, where an underlayer 902 of the patterning layer 506 is formedon the substrate 502. The underlayer may be a first (e.g., nearest thesubstrate) layer of the tri-layer patterning layer 506 and include asensitizer additive component 910. In an embodiment, an underlayermaterial of the underlayer 902 includes an organic material. In afurther embodiment, the organic material includes a plurality ofmonomers or polymers that are not cross-linked. In some embodiments, theunderlayer material may contain a material that is patternable and/orhave a composition tuned to provide anti-reflection properties. In someembodiments, the underlayer material includes a solvent. For example,the solvent may include an organic solvent may including dimethylsulfoxide (DMSO), tetrahydrofuran (THF), propylene glycol methyl ether(PGME), propylene glycol methyl ether acetate (PGMEA), n-Butyl acetate,Cyclohexanol, γ-Butyrolactone (GBL), ethanol, propanol, butynol,methanol, ethylene, glycol, gamabutylactone, N-Methyl-2-pyrrolidone(NMP), alkylsulfoxide, carboxylic ester, carboxylic acid, alcohol,glycol, aldehyde, ketone, acid anhydride, lactone, halogenated alkane,non-halogenated alkane, branched alkane, non-branched alkane, cyclicalkane, non-cyclic alkane, saturated alkane, non-saturated alkane, or acombination thereof.

In some embodiments, the sensitizer additive component 910 includes ametal that absorbs the radiation (e.g., the EUV light) in a EUV exposureto generate secondary electrons. In some embodiments, the metal may havean absorption coefficient of the EUV light greater than an absorptioncoefficient for the main elements (e.g., carbon, oxygen, and hydrogen)of the polymer and the acid generator in the underlayer and/or or otherlayers of the patterning layer 506. For example, the metal may includeone of Te, Pb, Sn, Ag, Bi, Sb, Cs, Ba, La, Ce, and In. For furtherexample, the metal may be a metal cation including one of Cs^(n1+),Ba^(n2+), La^(n3+), Ce^(n4+), where n1 is equal to or greater than 1,and each of the n2, n3, and n4 may be equal to or greater than 2. Insome examples, the metal may be a metal cation including one of In^(n+)and Ag^(n+), where n is an integer equal to or greater than 1. In someexamples, the metal may be a metal cation including Sn²⁺, Sn⁴⁺, or a Sncation having a charge magnitude that is greater than 4.

In some embodiments, the sensitizer additive component 910 may includeone or more anions, and bonds (e.g., ionic bond) are formed between themetal cation and each of the one or more anions. In some embodiments,each of the bonds may have a bonding energy large enough so that thebonds of the sensitizer additive component 910 are stable and do notbreak during a subsequent exposure process, and the sensitizer additivecomponent 910 remains substantially the same during the exposureprocess. In some examples, the anions include one or more of SO₃—, N—,COO—, CO₃—. In some examples, the bonding energy of each of the bondsmay be equal to or greater than about 100 kcal/mol. In some examples,the bonding energy of each of the bonds may be equal to or greater thanabout 150 kcal/mol.

Referring now to the examples of FIGS. 10A, 10B, 10C, 10D, 10E, 10F,10G, 10H, and 10I, in some embodiments, the sensitizer additivecomponent 910 is an isolated molecule that is not attached to a polymerchain. In some embodiments, the total molecular weight of the sensitizeradditive component 910 may be equal to or less than 1000. Referring tothe example of FIG. 10A, a sensitizer additive component 910 may includea metal cation 1002 bonded to one or more anions 1004 by bonds 1006. Inthe example of FIG. 10A, each anion 1004 is a protecting group which mayprotect the metal cation 1002 from undesired reactions.

In some embodiments, the sensitizer additive component 910 is soluble ina particular solvent (e.g., the solvent of the underlayer 902 and/orother layers of the patterning layer 506). In some embodiments, as thesolubility of the sensitizer additive component 910 is a function of theanion 1004, the solubility of the sensitizer additive component 910 maybe optimized by determining the anion 1004 based on the anion 1004'ssolubility in the solvent. In some examples, the anion 1004 may have acarbon number that is equal to or greater than four to achieve thedesired solubility in the solvent. In some embodiments, the sensitizeradditive component 910 is a single organometallic sensitizer.

In some embodiments, the bond 1006 between the metal cation 1002 and theanion 1004 of the sensitizer additive component 910 remainssubstantially the same during the exposure process. For example, thebond 1006 between the metal cation 1002 and the anion 1004 has a bondingenergy large enough so that the bond 1006 may remain stable and do notbreak during the exposure process. In some examples, the bonding energymay be equal to or greater than about 100 kcal/mol. In some embodiments,the total molecular weight of the sensitizer additive component 910 maybe equal to or less than 1000.

Referring now to FIGS. 10B, 10C, 10D, and 10E, in some embodiments, theprotecting groups 1004 remain substantially the same during the exposureprocess. The plurality of chemical formulas below (also shown in FIGS.10B, 10C, 10D, and 10E) represent some exemplary embodiments of thesensitizer additive component 910, where the sensitizer additivecomponent 910 is an isolated molecule not attached to a polymer chain,and the protecting groups 1004 of the sensitizer additive component 910remain substantially the same during the exposure process.

Referring now to the examples of FIGS. 10F, 10G, 10H, and 10I, in someembodiments, the protecting groups 1004 of the sensitizer additivecomponent 910 have a polarity switch function, and may be referred to asthe polarity switch protecting groups 1004 below. In some examples, thesensitizer additive component 910 including the polarity switchprotecting groups 1004 may exhibit hydrophobic properties prior toexposure. Referring to the example of FIG. 10F, in some embodiments, thepolarity switch protecting groups 1004 includes a carbon chain 1008(also referred to as a spacer 1008) attaching the metal cation 1002 to aR3 unit and a R4 unit. In some examples, the number of carbons in thecarbon chain 1008 may be between 1 and 10. In some examples, the numberof carbons in the carbon chain 1008 may be greater than 10. In someexamples, the carbon chain 1008 may include —CH2CH2CH2-, —CH2CH2COCH2-,—CH2CH2CH2CH2CH2-, —CH2COCH2-, and/or other suitable components. In someembodiments, the R3 unit may include one or more of —S—, —P—, —P(O₂)—,—C(═O)S—, —C(═O)O—, —O—, —N—, —C(═O)N—, —SO₂O—, —SO₂O—, —SO₂S—, —SO—,—SO₂—, and/or other suitable components. In some embodiments, the R4unit may include a tertiary carbon. For example, the R4 unit may includeone or more acid labile groups (ALGs). The chemical formulas belowrepresent some exemplary embodiments of the R4 unit.

Referring now to FIG. 10G, illustrated is an example of the sensitizeradditive component 910 where the R3 unit is —C(═O)O—. The plurality ofchemical formulas below (also shown in FIGS. 10H and 10I) represent someexemplary embodiments of the sensitizer additive component 910 includingpolarity switch protecting groups 1004.

Referring now to the examples of FIGS. 10J and 10K, in some embodiments,during or after exposure to radiation, the R3 unit of the polarityswitch protecting group 1004 may react with H⁺ (e.g., provided by PAGand/or TAG), and the R4 unit may leave the sensitizer additive component910. The resulting sensitizer additive component is referred to as thesensitizer additive component 910A. In some embodiments, the sensitizeradditive component 910A may exhibit hydrophobic properties. As such, thereaction between the R3 unit and the H⁺ and the leaving of the R4 unitmay make the material including the sensitizer additive component 910Amore hydrophilic in the regions exposed to radiation (e.g., regions of506A of FIG. 6) than those regions of non-exposure. In some embodiments,the sensitizer additive component 910 in those regions of non-exposureremains substantially the same during the exposure process. Referringnow to the example of FIG. 10J, illustrated is an examples of thesensitizer additive components 910A including the polarity switchprotecting groups 1004A bonded to the metal cation 1002 using the bond1006. Referring now to the example of FIG. 10K, illustrated is anexample of the resulting sensitizer additive component 910A after thesensitizer additive components 910 of FIG. 10G is exposed to radiation,where the R3 unit including —C(═O)O— has reacted with H⁺ to form—C(═O)OH. As such, in some embodiments, the hydrophilic nature of theexposed regions (e.g., regions of 506A of FIG. 6) including thesensitizer additive component 910A is increased, which may the contrastbetween exposed and non-exposed regions and allow for optical contrastimprovement. In some embodiments, the sensitizer additive component 910Amay help increase the exposed regions' dissolution rate in a developerused in the developing process.

Referring now to the examples of FIGS. 11A, 11B, 11C, and 11D, in someembodiments, the sensitizer additive component 910 may be bonded to apolymer chain. Illustrated in FIG. 11A is an exemplary copolymer 1100including a polymer chain 1102 and a sensitizer additive component 910attached to the polymer chain 1102. The polymer chain 1102 may be PHS(such as PHS polymers by DuPont™), acrylate, a 1-10 carbon unit, and/orother suitable polymer chain.

In the example of FIG. 11A, a metal cation 1002 of the sensitizeradditive component 910 may be bonded to an anion 1104 using a bond 1108where the anion 1104 is an R1 unit (also referred to as a polymer chainbonding component) attaching to the polymer chain 1102. The R1 unit maybe unbranched or branched, cyclic or noncyclic, and may includesaturated 1-9 carbon unit with hydrogen or halogen (e.g., alkyl,alkene), —S—, —P—, —P(O₂)—, —C(═O)S—, —C(═O)O—, —O—, —N—, —C(═O)N—,—SO₂O—, —SO₂O—, —SO₂S—, —SO—, —SO₂—, carboxylic acid, ether, ketone,ester unit and/or other suitable components. In some embodiments, thebonding energy of the bond 1108 is sufficiently large so that the bond1108 is stable and does not break during the exposure process. Forexample, the bonding energy of the bond 1108 is equal to or greater thanabout 100 kcal/mol. Referring to the example of FIGS. 11A, 11B, and 11C,in some embodiments, the metal cation 1002 of the sensitizer additivecomponent 910 may be bonded to one or more protecting groups 1004 usingbonds 1006. In some examples, the bond energy of the bond 1006 may beequal to or greater than about 100 kcal/mol so that the bond 1006 isstable and does not break during the subsequent exposure process.Referring to the example of FIG. 11D, in some embodiments, the metalcation 1002 is not bonded to any protecting groups.

The plurality of chemical formulas below (also shown in FIGS. 11B, 11C,11D) represent some exemplary embodiments of the copolymer 1100:

In some embodiments, the underlayer 902 may be formed by depositing amixed material formed by mixing the underlayer material and a sensitizeradditive material including the sensitizer additive component 910. Insome embodiments, the mixed material is formed as a blending polymer (orpolymer blend). The polymer blend may be a heterogeneous or homogeneousblend. In some embodiments, the mixed material is formed bycopolymerization of the components. In other words, the sensitizeradditive component is a copolymer of the underlayer material.

In an embodiment, the percentage by weight of the sensitizer additivecomponents to a base polymer of the underlayer material is in a rangefrom about 0.1% to about 10%. In an embodiment, the percentage is about5%. In an embodiment, the percentage of the sensitizer additivecomponents to the base polymer is the percentage at deposition. Thepercentage of the sensitizer additive components may provide control ofacid generation and the transmittance of the patterning layer 506.

In some embodiments, the underlayer 902 may be formed by a spin-oncoating process, chemical vapor deposition process (CVD), physical vapordeposition (PVD) process, and/or other suitable deposition processes. Inan embodiment, the underlayer is omitted. In an embodiment, theunderlayer does not include the sensitizer additive component 910.

The method 200 then proceeds to block 204, where a middle layer of thepatterning layer 506 is formed over the substrate and/or the underlayer.The middle layer may be a second layer of a tri-layer patterning layer.In some embodiments, the middle layer may have a composition thatprovides an anti-reflective properties and/or hard mask properties forthe lithography process. In an embodiment, the middle layer includes asilicon containing layer (e.g., a silicon hard mask material). Themiddle layer may include a silicon-containing inorganic polymer. In afurther embodiment, the middle layer includes a siloxane polymer (e.g.,a polymer having a backbone of O—Si—O—Si— etc.). The silicon ratio ofthe middle layer material may be controlled such as to control the etchrate. In other embodiments the middle layer may include silicon oxide(e.g., spin-on glass (SOG)), silicon nitride, silicon oxynitride,polycrystalline silicon, a metal-containing organic polymer materialthat contains metal such as titanium, titanium nitride, aluminum, and/ortantalum; and/or other suitable materials.

Referring now to the example of FIG. 9, a middle layer 904 is disposedon the underlayer 902 as one component of the tri-layer patterning layer506. The middle layer 904 may include a suitable material such as a hardmask material.

In some embodiments, the middle layer 904 may be formed by depositing amaterial including a mixture of the middle layer material and asensitizer additive material including the sensitizer additive component910. The mixture including the sensitizer additive component 910 may beformed substantially similar to the mixture of the sensitizer additivematerial and the underlayer material discussed above with reference theunderlayer 902 of FIG. 9.

In some embodiments, the sensitizer additive material and a middle layermaterial are mixed prior to depositing on a substrate. In an embodiment,the percentage by weight of the sensitizer additive component to a basepolymer of the middle layer material is in a range from about 0.1% toabout 10%. In an embodiment, the percentage is about 5%. In anembodiment, the percentage of the sensitizer additive component to thebase polymer is the percentage at deposition. The percentage of thesensitizer additive component may provide control of acid generation andthe transmittance of the patterning layer 506. In some embodiments, themiddle layer 904 may be formed by a spin-on coating process, chemicalvapor deposition process (CVD), physical vapor deposition (PVD) process,and/or other suitable deposition processes. In an embodiment, the middlelayer is omitted. In an embodiment, the middle layer does not includethe sensitizer additive component 910.

The method 200 then proceeds to block 206 where a photoresist layer isformed over the middle layer. The photoresist layer may be a third, andtop, layer of a tri-layer patterning layer. The photoresist layer may bea photosensitive layer operable to be patterned by a radiation as knownin the art. The photoresist layer may include a photoresist (e.g., achemical amplified (CA) resist), which is a radiation (e.g., light)sensitive material and may be a positive tone resist (PTD) or negativetone resist (NTD). A positive tone resist (or simply positive resist) isa type of photoresist in which the portion of the photoresist that isexposed to light becomes soluble to the photoresist developer. Theportion of the photoresist that is unexposed remains insoluble to thephotoresist developer. A negative tone resist (or simply negativeresist) is a type of photoresist in which the portion of the photoresistthat is exposed to light becomes insoluble to the photoresist developer.The unexposed portion of the photoresist is dissolved by the photoresistdeveloper.

Specifically, the resist may include an organic polymer (e.g., positivetone or negative tone photoresist polymer), an organic-based solvent,and/or other suitable components known in the art. Other components mayinclude a photo-acid generator (PAG) component, a thermal acid generator(TAG) component, a quencher component, a photo-decomposable base (PDB)component, and/or other suitable photosensitive component depending onthe resist type. In some embodiments, when absorbing photo energy froman exposure process, the PAG forms a small amount of acid. The resistmay include a polymer material that varies its solubility to a developerwhen the polymer is reacted with this generated acid. Examples ofsuitable PAGs include salts of sulfonium cations with sulfonates, saltsof iodonium cations with sulfonates, sulfonyldiazomethane compounds,N-sulfonyloxyimide PAGs, benzoinsulfonate PAGs, pyrogallol trisulfonatePAGs, nitrobenzyl sulfonate PAGs, sulfone PAGs, glyoxime derivatives,triphenylsulfonium nonaflate, and/or other suitable PAGs now known orlater developed.

Exemplary organic based solvents include but are not limited to PGMEA(propylene glycol monomethyl ether acetate)(2-methoxy-1-methylethylacetate), PGME (propylene glycol monomethylether), GBL (gamma-butyrolacetone), cyclohexanone, n-butyl acetate, and2-heptanone. The organic polymer resin of the photosensitive materialmay include those resists formulated for KrF, ArF, immersion ArF, EUV,and/or e-beam lithography processes. Examples include Novolak (a phenolformaldehyde resin), PHS (poly(4-hydroxystyrene) derivatives), polyaliphatic resist, phenolic derivative, and/or other suitableformulations. In some embodiments, the organic polymer resion mayinclude a cleavable group (ALG) and a non-cleavage group (e.g., alactone unit, a polar unit).

In some embodiments, the photoresist layer 906 may include sensitizeradditive component 910, which may be substantially similar to thesensitizer additive component 910 of the underlayer 902 discussed above.In some embodiments, the photoresist layer 906 may be formed bydepositing a material including a mixture of the photoresist layermaterial and a sensitizer additive material including the sensitizeradditive component 910. The mixture of the photoresist layer materialand the sensitizer additive material may be formed substantially similarto the mixture of the sensitizer additive material and the underlayermaterial discussed above with reference the underlayer 902 of FIG. 9.

In an embodiment, the percentage by weight of the sensitizer additivecomponent to a base polymer of the photoresist material is in a rangefrom about 0.1% to about 10%. In an embodiment, the percentage of thesensitizer additive component to the base polymer is the percentage atdeposition. The percentage of the sensitizer additive component mayprovide control of acid generation and the transmittance of thepatterning layer 506. For example, excessive sensitizer additivecomponent 910 may lower the transmittance of the photoresist layer 906,thereby affecting its performance. In an embodiment, the percentage byweight of the sensitizer additive component to a base polymer of thephotoresist material may be in a range from about 0.1% to about 3%.

In some embodiments, the concentration of the sensitizer additivecomponent 910 in the photoresist layer 906 may have substantiallygreater effect on the transmittance of the photoresist layer 906 thanthe concentration of the sensitizer additive component 910 in otherlayers (e.g., the underlayer 902, the middle layer 904) of thepatterning layer 506. As such, in some embodiments, the sensitizeradditive amount in the photoresist layer 906 is lower than thesensitizer additive component amount in the other layers. In someexamples, the percentage by weight of the sensitizer additive component910 in the photoresist layer 906 is less than the percentage by weightof the sensitizer additive component 910 in the underlayer 902 or in themiddle layer 904 (e.g., by at least about 50% by weight).

In some embodiments, the photoresist layer 906 may be formed by aspin-on coating process, chemical vapor deposition process (CVD),physical vapor deposition (PVD) process, and/or other suitabledeposition processes. In an embodiment, the photoresist layer 906 doesnot include the sensitizer additive component 910.

While in the illustrated example of FIG. 9 each layer of the patterninglayer 506 includes the sensitizer additive component 910, it isunderstood that in various embodiments, one or more layers of thepatterning layer 506 may not include the sensitizer additive component910. In some examples, the photoresist layer 906 does not include thesensitizer additive component 910, while one or both of the underlayer902 and the middle layer 904 may include the sensitizer additivecomponent 910. In some examples, the photoresist layer 906 may includethe sensitizer additive component 910, while one or both of theunderlayer 902 and the middle layer 904 do not include the sensitizeradditive component 910. In various embodiments, the concentration of thesensitizer additive component 910 may be designed based on the variousproperties and concentrations of the TAG, PAG, and/or quencher in one ormore of the layers of the patterning layer 506 to reach a balanceperformance between sensitivity and LWR. In various embodiments, theunderlayer 902, the middle layer 904, and the photoresist layer 906 mayhave various sensitizer additive component concentration profiles. Insome embodiments, the sensitizer additive component 910 may besubstantially uniformly distributed in the underlayer 902, the middlelayer 904, and/or the photoresist layer 906. In some embodiments, theunderlayer 902, the middle layer 904, and the photoresist layer 906 mayhave different sensitizer additive component concentration profiles. Inone example, the sensitizer additive component 910 is uniformlydistributed in the underlayer 902 and/or the middle layer 904, while thephotoresist layer 906 may have a non-uniform sensitizer additivematerial concentration profile (e.g., varied continuously or variedstepwise). In some examples, the concentration of the sensitizeradditive component may increase with a gradient from a top surface ofthe photoresist layer 906 to a bottom surface of the photoresist layer906.

Referring now to the examples of FIGS. 12A, 12B, 12C, and 12D, in someembodiments, one or more of the underlayer 902, the middle layer 904,and the photoresist layer 906 may include a floating additive material.In some embodiments, the floating additive material may include afloating unit. In some embodiments, after deposition, the sensitizeradditive component 910 in the deposited layer may be volatile anddiffuse out of the deposited layer. A floating additive layer formed bythe floating additive material may act as a diffusion barrier layer sothat the sensitizer additive component 910 remains in the depositedlayer. For example, after deposition, the floating additive material mayform an upper layer or region at the top of the deposited layer. In anembodiment, the properties of the floating additive material allow thelayer or region provided to be disposed at and/or move such that a layerof the floating additive material is formed at the top of the depositedlayer. In other words, the properties of the polymer of the floatingadditive material allow it to “float” to the top of the deposited layer.The floating may be provided by a floatable component or unit attachedto a polymer chain of the floating additive material. In someembodiments, the floating additive material may also provide one of anacid generator component or a base generator component, for example,also attached to the polymer chain. The acid generator component or basegenerator component can generate an acid or a base after exposure to aradiation and/or thermal treatment. In one example, the acid generatorcomponent may generate acid by reacting with the secondary electronsgenerated by the sensitizer additive component 910 in various layers(e.g., one or more of the underlayer 902, the middle layer 904, thephotoresist layer 906) of the patterning layer 506.

Referring now to FIGS. 12A, 12B, and 12C, illustrated is an exemplarypatterning layer 506 including a floating additive material. Referringto the example of FIG. 12A, the underlayer 902 is formed by depositing amaterial including an underlayer material, a sensitizer additivematerial, and a floating additive material on the substrate. After thedeposition, the floating additive material 1202 in the underlayer 902may form a floating additive layer 1204 at the top of the underlayer902, thereby preventing the volatile sensitizer additive component 910from diffusing out of the underlayer 902. Referring to the example ofFIG. 12B, a middle layer 904 is disposed over the underlayer 902 and thefloating additive layer 1204. In the example illustrated in FIG. 12B,the floating additive layer 1204 may move to the top of the middle layer904. Alternatively, in some embodiments, the floating additive layer1204 may not move to the top of the middle layer 904 and remain disposedbetween the underlayer 902 and the middle layer 904. In an example, thefloating additive layer 1204 disposed between the underlayer 902 and themiddle layer 904 may act as a barrier layer so that the sensitizeradditive component 910 remains in the underlayer 902, which may helpcontrol the concentrations of the sensitizer additive component 910 inthe various layers of the patterning layer 506. Referring now to theexample of FIG. 12C, a photoresist layer 906 is formed over the middlelayer 904 and the floating additive layer 1204. In the exampleillustrated in FIG. 12C, after the photoresist layer 906 is deposited,the floating additive layer 1204 may move to the top of the photoresistlayer 906. Alternatively, in some embodiments, the floating additivelayer 1204 may not move to the top of the photoresist layer 906, andremain disposed between the middle layer 904 and the photoresist layer906.

In various embodiments, one or more of the middle layer 904 and thephotoresist layer 906 may include both the sensitizer additive component910 and a floating additive material 1202. In some embodiments, afterthe middle layer 904 including a floating additive material 1202 isdeposited, the floating additive material 1202 may form a floatingadditive layer 1204 at the top of the middle layer 904, therebypreventing the volatile sensitizer additive component 910 in the middlelayer 904 from diffusing out of the middle layer 904. In someembodiments, after the photoresist layer 906 is deposited, the floatingadditive layer 1204 moves to the top of the photoresist layer 906.Alternatively, the floating additive layer 1204 may remain disposedbetween the middle layer 904 and the photoresist layer 906 and act as abarrier so that the sensitizer additive component 910 remains in themiddle layer 904 and does not diffuse into the photoresist layer 906,which may help control the concentrations of the sensitizer 910 in themiddle layer 904 and the overlying photoresist layer 906.

In some embodiments, after the photoresist layer 906 including afloating additive material 1202 is deposited, the floating additivematerial 1202 may form a floating additive layer 1204 at the top of thephotoresist layer 906, thereby preventing the volatile sensitizeradditive component 910 in the photoresist layer 906 from diffusing outof the photoresist layer 906.

The floating additive material is now described in further detail. Thefloating additive material may include a polymer having a floatableunit. In some embodiments, the floating additive material may includeone of an acid or a base component. The floatable unit and acid/basecomponent may be bonded together by a polymer backbone. Illustrated inFIG. 12D is an example of a floatable unit 1208 attached to the polymer1206 illustrated as a floating additive material 1202. The polymer chain1206 may be PHS (such as PHS polymers by DuPont™), acrylate, a 1-10carbon unit, and/or other suitable polymer chain. A CxFy unit is bondedto the polymer chain 402. The CxFy may provide the “floating” propertiesof the additive material, such as the additive material 400 of FIG. 4 ofthe additive material 500 of FIG. 5. The CxFy component may be a chainor branched unit. The number of carbons (x) may be between one (1) andnine (9), including 1 and 9. The number of florines (y) may be greaterthan 0 (e.g., between one (1) and nine (9), including 1 and 9).

In some embodiments, a R2 component may connect the CxFy unit to thepolymer chain 1206. In other embodiments, the R2 component is omittedand the CxFy unit is connected directly to the polymer chain 1206. TheR2 unit may be unbranched or branched, cyclic or noncyclic, and mayinclude saturated 1˜9 carbon unit with hydrogen or halogen (e.g., alkyl,alkene), or —S—, —P—, —P(O₂)—, —C(═O)S—, —C(═O)O—, —O—, —N—, —C(═O)N—,—SO₂O—, —SO₂O—, —SO₂S—, —SO—, —SO₂—, carboxylic acid, ether, ketone,ester unit and/or other suitable components.

Exemplary floating unit 1202 components may include one of thefollowing:

Referring now to FIGS. 3, 13, and 14, illustrated is another exemplaryembodiment of a method 300 of forming a patterning layer including asensitizer additive component at block 104 of the method 100. In suchembodiments of the method 300, the sensitizer additive component in thepatterning layer is formed using a doping process.

Referring to FIG. 3 and the example of FIG. 13, the method 300 starts atblock 302, where an underlayer 902 is formed over the substrate 502.Block 302 may be substantially similar to block 202. In the exampleillustrated in FIG. 13, the underlayer 902 does not include thesensitizer additive component at this stage of the process. The method300 proceeds to block 304, where a middle layer 904 is formed over theunderlayer. Block 304 may be substantially similar to block 204. In theexample illustrated in FIG. 13, the middle layer 904 does not includethe sensitizer additive component at this stage of the process. Themethod 300 then proceeds to block 306, where a photoresist layer isformed over the middle layer 904. Block 306 may be substantially similarto block 306. In the example illustrated in FIG. 13, the middle layer906 does not include the sensitizer additive component at this stage ofthe process.

In some embodiments, one or more of the underlayer 902, middle layer904, and photoresist layer may include a floating additive material1202, thereby forming one or more floating additive layers 1204. In theexample of FIG. 13, a first floating additive layer 1204 is disposedover the photoresist layer 906, and a second floating additive layer1204 is disposed between the middle layer 904 and the photoresist layer906. However, it is understood that various configurations of thefloating additive layers 1204 in the patterning layer 506 may be used toreduce the diffusion of the sensitizer additive and control theconcentration and distribution of the sensitizer additive component inthe various layers of the patterning layer 506. In some examples, afloating additive layers 1204 may be disposed between the underlayer 902and the middle layer 904. In some examples, there is no floatingadditive layer 1204 disposed over the photoresist layer 906.

The method 300 then proceeds to block 308, where a doping process isperformed to the patterning layer 506, so that the sensitizer additivecomponent 910 is formed in one or more of the underlayer, the middlelayer, and the photoresist layer. Referring now to FIG. 13, a dopingprocess 1302 is performed to the patterning layer 506 of a device 1300.In some embodiments, the doping process 1302 includes an ionimplantation process implanting ions into one or more of the underlayer,the middle layer, and the photoresist layer. In some embodiments, thedopant may include at least one of Te, Pb, Sn, Ag, Bi, Sb, Cs, Ba, La,Ce, and Ln. For further example, the dopant may include Cs^(n+,)Ba^(n2+), La^(n3+), and/or Ce^(n4+), where n1 is equal to or greaterthan 1, and each of n2, n3, and n4 is equal to or greater than 2. Insome examples, the dopant may include a metal cation including one ofIn^(n+) and Ag^(n+), where n is an integer equal to or greater than 1.In some examples, the dopant may include Sn²⁺, Sn⁴⁺, and/or a Sn metalcation having an order higher than 4.

In some embodiments, the dopant may include one or more of theprotective groups 1004. In some embodiments, the implanted ions mayattach to each other or components in the underlayer, middle layer, orphotoresist layer to form the sensitizer additive component 910. In someembodiments, the resulting sensitizer additive component 910 in one ormore of the underlayer, the middle layer, and the photoresist layer maybe substantially similar to the sensitizer additive component 910discussed above with references to FIGS. 10A-11D.

In various embodiments, the sensitizer additive component concentration(e.g., by controlling dopant species, ion beam energy, implantationdose, implantation depth of the ion implantation process 1302) so as toresult in desired concentration and concentration profile of thesensitizer additive component. In some embodiments, the ion implantationprocess includes multiple implantation steps to achieve the desiredsensitizer additive component concentration.

Referring now to the example of FIG. 14, illustrated is the device 1300after the doping process is performed. In some embodiments, the variouslayers of the patterning layer 506 may have different sensitizeradditive component concentration. In some examples, the photoresistlayer 906 may have a sensitizer additive component concentration lessthan the sensitizer additive component concentration in the underlayer902 and/or the middle layer 904 (e.g., by at least 50% by weight). Insome examples, the photoresist layer 906 has a concentration of thesensitizer additive component 910 of about 0.1% by weight or includessubstantially no sensitizer additive component 910, while the middlelayer 904 has a concentration of the sensitizer additive component 910of about 5% by weight, and the underlayer 902 has a concentration of thesensitizer additive component 910 of about 10% by weight.

In some embodiments, the underlayer 902, the middle layer 904, and thephotoresist layer 906 may have various sensitizer additive componentconcentration profiles. In some embodiments, the sensitizer additivecomponent 910 may be substantially uniformly distributed in theunderlayer 902, the middle layer 904, and/or the photoresist layer 906.In some embodiments, the underlayer 902, the middle layer 904, and thephotoresist layer 906 may have different sensitizer additive componentconcentration profiles. In one example, the sensitizer additivecomponent 910 is uniformly distributed in the underlayer 902 and/or themiddle layer 904, while the photoresist layer 906 may have a non-uniformsensitizer additive material concentration profile (e.g., variedcontinuously or varied stepwise). For example, the concentration of thesensitizer additive component may increase with a gradient from a topsurface of the photoresist layer 906 to a bottom surface of thephotoresist layer 906. For further example, a top portion of thephotoresist layer 906 may include about less than about 0.1% sensitizeradditive component, while a bottom portion of the photoresist layer 906may include about 1% sensitizer additive mate component. For furtherexample, the non-uniform sensitizer additive component concentrationprofile of the photoresist layer 906 may be designed based on thetransmittance profile of the photoresist layer 906 to achieve uniformacid generation.

It is noted that while in the example of FIG. 14 all layers of thepatterning layer 506 include the sensitizer additive component 910 afterthe doping process is performed, it is understood that one or more ofthe underlayer 902, the middle layer 904, and the photoresist layer 906of the patterning layer 506 may include substantially no sensitizeradditive component 910 after the doping process is performed. In someexamples, the photoresist layer 906 may include substantially nosensitizer additive component 910 after the doping process is performed.

Referring now to the example of FIGS. 4A, 4B, 4C, 4D, 15A, 15B, 15C, and15D, illustrated are exemplary embodiments forming a patterning layerincluding a sensitizer additive component at block 104 of the method100. In such embodiments, the patterning layer 506 may include one ormore sensitizer additive layers 1402 disposed between the layers oftri-layer patterning layer 506 formed by deposition or coating. This isillustrated by the semiconductor device 15A, 15B, 15C, and 15D.

Referring now to FIGS. 4A and 15A, illustrated is an exemplaryembodiment of a method 400 forming a patterning layer 506 includingsensitizer additive component 910 at block 104 of the method 100. Themethod 400 starts at block 402, where a sensitizer additive layer 1402is formed over the substrate 502. In some embodiments, the sensitizeradditive layer 1402 may include a sensitizer additive layer material. Insome embodiments, the sensitizer additive layer material may include anorganic material. In a further embodiment, the organic material includesa plurality of monomers or polymers that are not cross-linked. In someembodiments, the sensitizer additive layer material includes a solvent.For example, the solvent may include an organic solvent may includingdimethyl sulfoxide (DMSO), tetrahydrofuran (THF), propylene glycolmethyl ether (PGME), propylene glycol methyl ether acetate (PGMEA),n-Butyl acetate, Cyclohexanol, γ-Butyrolactone (GBL), ethanol, propanol,butynol, methanol, ethylene, glycol, gamabutylactone,N-Methyl-2-pyrrolidone (NMP), alkylsulfoxide, carboxylic ester,carboxylic acid, alcohol, glycol, aldehyde, ketone, acid anhydride,lactone, halogenated alkane, non-halogenated alkane, branched alkane,non-branched alkane, cyclic alkane, non-cyclic alkane, saturated alkane,non-saturated alkane, or a combination thereof.

In some embodiments, the sensitizer additive layer 1402 may be formed bydepositing a material including a mixture of a sensitizer additive layermaterial and a sensitizer additive material including the sensitizeradditive component 910. The mixture of the sensitizer additive layermaterial and the sensitizer additive material may be substantiallysimilar to the mixture of the sensitizer additive material and theunderlayer material described above with reference to FIG. 9.

In some embodiments, the sensitizer additive layer 1402 may include afloating additive material 1202 substantially similar to the floatingadditive material 1202 described above with reference to FIGS. 12A, 12B,12C, and 12D. After depositing, the floating additive material 1202 maymove up to the top of the sensitive additive layer 1402 and form afloating additive layer 1204.

The sensitizer additive layer 1402 may be formed by a spin-on coatingprocess, chemical vapor deposition process (CVD), physical vapordeposition (PVD) process, and/or other suitable deposition processes.

Referring now to FIGS. 4A and 15A, the method 400 then proceeds to block404, where an underlayer 902 is formed over the sensitizer additivelayer 1402. Block 404 may be substantially similar to block 202 of themethod 200. The method 400 then proceeds to block 406, where a middlelayer 904 is formed over the under layer 902. Block 406 may besubstantially similar to block 204 of the method 200. The method 400then proceeds to block 408, where a photoresist layer 906 is formed overthe middle layer 904. Block 408 may be substantially similar to block206 of the method 200.

Referring now to FIGS. 4B, 4C, 4D, 15B, 15C, and 15D, in variousembodiments, the patterning layer 506 may include one or more sensitizeradditive layers disposed between or over the underlayer 902, middlelayer 904, and photoresist layer 906. The same description providedabove with reference to FIGS. 4A and 15A regarding the underlayer 902,middle layer 904, and photoresist layer 906 and the sensitizer additivelayer 1402 applies except with the differences noted below.

Referring now to FIGS. 4B and 15B, in an exemplary embodiment of amethod 420, at block 422, an underlayer 902 is formed over thesubstrate. The method 420 proceeds to block 422, where a middle layer isformed over the underlayer. The method 420 then proceeds to block 426,where a sensitizer additive layer 1402 is formed between the middlelayer 904 and photoresist layer 906. The method 420 proceeds to block428, where a photoresist layer is formed over the sensitizer additivelayer 1402.

Referring now to FIGS. 4C and 15C, in an embodiment of a method 440, atblock 442, an underlayer 902 is formed over the substrate. The method440 proceeds to block 444, where a middle layer 904 is formed over theunderlayer 902. The method 440 then proceeds to block 446, where aphotoresist layer 906 is formed over the middle layer 904. The method440 then proceeds to block 448, where a sensitizer additive layer 1402is formed over the photoresist layer 906.

Referring now to FIGS. 4D and 15D, in an embodiment of a method 460, atblock 462, an underlayer 902 is formed over the substrate. The method460 proceeds to block 464, where a middle layer is formed over theunderlayer. The method 460 then proceeds to block 466, where a firstsensitizer additive layer 1402A is formed over the middle layer 904. Themethod 460 proceeds to block 468, where a photoresist layer is formedover the first sensitizer additive layer 1402A. The method 460 thenproceeds to block 470, where a second sensitizer additive layer 1402B isformed over the photoresist layer 906. In some embodiments, thesensitizer additive component concentration in the second sensitizeradditive layer 1402B may have a substantially greater effect on thetransmittance of the photoresist layer 906 than the sensitizer additivecomponent concentration in the first sensitizer additive layer 1402A. Assuch, in some examples, the first sensitizer additive layer 1402A mayhave a sensitizer additive component concentration higher than thesensitizer additive component concentration of the second sensitizeradditive layer 1402B (e.g., by at least about 50% by weight)

In various embodiments, the sensitizer additive layers 1402, 1402A,and/or 1402B may have various sensitizer additive componentconcentration profiles. In some examples, the sensitizer additivecomponent 910 is uniformly distributed in the sensitizer additive layers1402, 1402A, and/or 1402B. In some examples, one or more of thesensitizer additive layers 1402, 1402A, and/or 1402B may have anon-uniform sensitizer additive material concentration profile (e.g.,varied continuously or varied stepwise).

Referring now to the example of FIG. 16, photo-acid generation in thepatterning layer 506 during an exposure process is illustrated. Asillustrated in FIG. 16, a photoresist layer 906 is disposed over a layer1602. The layer 1602 may be an underlayer 902, a middle layer 904,and/or a sensitizer additive layer 1402 disposed under the photoresistlayer 906. A sensitizer additive layer 1402 is disposed over thephotoresist layer 906. In some embodiments, during the exposure processat block 106, sensitizer additive components 910A, 910B, and 910C invarious layers of the patterning layer 506 may absorb the EUV light andgenerate secondary electrons, which may be used by acid generators inthe photoresist layer 906 to generate an acid. For example, each ofsensitizer additive component 910A in the photoresist layer 906,sensitizer additive component 910B in the sensitizer additive layer1402, and sensitizer additive component 910C in the layer 1602 mayabsorb a EUV light and generating a secondary electron. The secondaryelectron's energy may be used by acid generators 1606 (e.g., a TAG, aPAG) in the photoresist layer 906 to generate an acid.

Various advantages may be present in one or more embodiments of themethods, devices and compositions described herein. It is understood,however, that other embodiments may offer additional advantages, and notall advantages are necessarily disclosed herein, and that no particularadvantage is required for all embodiments. One advantage is that thepatterning layer offers improved lithography performance. By using asensitizer additive component including an element that has anabsorption coefficient of the EUV light greater than an absorptioncoefficient for the main elements (e.g., carbon, oxygen, and hydrogen)in the patterning layer, EUV light absorption is improved. Consequently,the acid generator is more efficient in generating the acid, which leadsto better photoresist sensitivity. Another advantage is that one or bothof a floating additive layer and a topcoat layer may be used to reducethe diffusion of the sensitizer additive component, thereby controllingthe concentration of the sensitizer additive component in various layersof the patterning layer. Yet another advantage is that a doping processmay be used to add the sensitizer additive component to the patterninglayer, which may help achieve various sensitizer additive concentrationprofiles in the various layers of the patterning layer. Yet anotheradvantage is that the sensitizer additive component may include apolarity switch protecting group and exhibit hydrophilic propertiesafter exposure to radiation, thereby providing for increasedhydrophilicity of exposed regions of the photoresist material.

Thus, in one embodiment described herein a method of making asemiconductor device is provided that includes providing a semiconductorsubstrate. A layer including an additive component is formed over thesemiconductor substrate. The additive component includes a metal cation.One or more bonds bonding the metal cation and one or more anions areformed. Each of the one or more anions is one of a protecting group anda polymer chain bonding component. The polymer chain bonding componentis bonded to a polymer chain of the layer. The semiconductor substrateis exposed to a radiation beam.

In an embodiment, a method is described which includes forming aphotosensitive layer over a substrate. The photosensitive layer includesan additive component. The additive component includes a metal and atleast one of a protecting group and a polymer chain bonding component.The polymer chain bonding component is bonded to a polymer chain of thephotosensitive material. The metal is bonded to the at least one of theprotecting group and the polymer chain bonding component using one ormore bonds. The photosensitive layer is selectively exposed to aradiation beam. A developer is applied to the photosensitive layer,which removes regions of the photosensitive layer exposed to theradiation beam.

In an embodiment, a method of semiconductor device fabrication isdescribed which includes forming a first additive layer on a targetsubstrate. The first additive layer includes an additive componentincluding a metal. A photoresist layer include an acid generator isformed adjacent to the first additive layer. The target substrate havingthe first additive layer and the photoresist layer disposed thereon isexposed using a radiation. The additive component of the first additivelayer absorbs the radiation and generates a secondary electron. The acidgenerator of the photoresist layer generates an acid using energy of thesecondary electron.

The foregoing has outlined features of several embodiments. Thoseskilled in the art should appreciate that they may readily use thepresent disclosure as a basis for designing or modifying other processesand structures for carrying out the same purposes and/or achieving thesame advantages of the embodiments introduced herein. Those skilled inthe art should also realize that such equivalent constructions do notdepart from the spirit and scope of the present disclosure, and thatthey may make various changes, substitutions and alterations hereinwithout departing from the spirit and scope of the present disclosure.

What is claimed is:
 1. A method of making a semiconductor device, themethod comprising: providing a semiconductor substrate; forming a layerincluding a polymer chain, a floating additive component, and a volatileadditive component over the semiconductor substrate, wherein thevolatile additive component includes a metal cation, and wherein theforming the layer further includes: forming one or more bonds bondingthe metal cation and one or more anions, wherein each of the one or moreanions is one of a protecting group and a polymer chain bondingcomponent, and wherein the polymer chain bonding component is bonded tothe polymer chain of the layer; floating the floating additive componentto a region that is adjacent to a top surface of the layer; and exposingthe layer to a radiation beam.
 2. The method of claim 1, wherein the oneor more bonds remain substantially the same during the exposing thelayer to the radiation beam.
 3. The method of claim 1, wherein the metalcation is a cation of a metal selected from the group consisting of Cs,Ba, La, and Ce.
 4. The method of claim 1, wherein the protecting groupincludes at least four carbon atoms.
 5. The method of claim 1, whereinthe polymer chain bonding component includes at least one selected fromthe group consisting of a 1˜9 carbon unit with hydrogen or halogen, —S—,—P—, —P(O₂)—, —C(═O)S—, —C(═O)O—, —O—, —N—, —C(═O)N—, —SO₂O—, —SO₂S—,—SO—, —SO₂—, carboxylic acid, ether, ketone, and ester unit.
 6. Themethod of claim 1, wherein the one or more bonds further includes: afirst bond bonding the metal cation and the protecting group; and asecond bond between the metal cation and the polymer chain bondingcomponent.
 7. The method of claim 6, wherein the protecting groupincludes the following chemical formula:

wherein

is bonded to the metal cation by the first bond and includes a carbonchain including a carbon number between 1 and 10, wherein R3 includes amaterial selected from the group consisting of —S—, —P—, —P(O₂)—,—C(═O)S—, —C(═O)O—, —O—, —N—, —C(═O)N—, —SO₂O—, —SO₂S—, —SO—, —SO₂—, andcombinations thereof, and wherein R4 includes a tertiary carbon.
 8. Amethod, comprising: forming a photosensitive layer over a substrate,wherein the photosensitive layer comprises a polymer chain and anadditive component, wherein the additive component includes: a metalselected from the group consisting of Cs, Ba, La, and Ce; and aprotecting group bonded to the metal by a first bond; a polymer chainbonding component bonded to the metal by a second bond, the polymerchain bonding component being further bonded to the polymer chain of thephotosensitive layer by a third bond, wherein the protecting groupincludes the following chemical formula:

wherein

includes a carbon chain including a carbon number between 1 and 10, the

being bonded to the metal by the first bond, wherein R3 includes amaterial selected from the group consisting of —S—, —P—, —P(O₂)—,—C(═O)S—, —C(═O)O—, —O—, —N—, —C(═O)N—, —SO₂O—, —SO₂S—, —SO—, —SO₂—, andcombinations thereof, and wherein R4 includes a tertiary carbon;selectively exposing the photosensitive layer to a radiation beam; andapplying a developer to the photosensitive layer, wherein the developerremoves regions of the photosensitive layer exposed to the radiationbeam.
 9. The method of claim 8, wherein prior to the exposure, theadditive component in the photosensitive layer exhibits hydrophobicproperties, and wherein after the exposure, the additive component inthe regions of the photosensitive layer exposed to the radiation beamexhibits hydrophilic properties.
 10. The method of claim 9, furthercomprising: during the exposure, R3 of the protecting group reacts withH⁺ provided by an acid generator of the photosensitive layer.
 11. Themethod of claim 10, further comprising: during the exposure, R4 of theprotecting group leaves the protecting group.
 12. The method of claim 8,wherein the photosensitive layer further includes a floating additivecomponent, and wherein the forming the photosensitive layer furtherincludes: floating the floating additive component to a region adjacenta top surface of the photosensitive layer.
 13. The method of claim 8,further comprising: depositing a topcoat layer over the photosensitivelayer.
 14. The method of claim 8, wherein the forming the photosensitivelayer includes: performing a doping process to form the additivecomponent in the photosensitive layer.
 15. A method of making asemiconductor device, the method comprising: providing a semiconductorsubstrate; forming a layer including a metal additive component and afloating additive component over the semiconductor substrate, whereinthe metal additive component includes a metal cation, and wherein theforming the layer further includes: forming one or more bonds bondingthe metal cation and one or more anions, wherein each of the one or moreanions is one of a protecting group and a polymer chain bondingcomponent, wherein the polymer chain bonding component is bonded to apolymer chain of the layer; and exposing the layer to a radiation beam,wherein prior to the exposing the layer to the radiation beam, the metaladditive component exhibits hydrophobic properties, and wherein afterthe exposing the layer to the radiation beam, the metal additivecomponent in regions of the layer exposed to the radiation beam exhibitshydrophilic properties.
 16. The method of claim 15, wherein the formingthe layer further comprises: mixing a first material and an additivematerial including the metal additive component to form a mixture,wherein the mixture is one of a copolymer of the first material and themetal additive component and a blending polymer of the first materialand the metal additive component; and depositing the mixture on thesemiconductor substrate to form the layer.
 17. The method of claim 16,wherein the mixture includes the floating additive component, furthercomprising: after the depositing the mixture, floating the floatingadditive component to a top region of the layer.
 18. The method of claim15, wherein the protecting group includes the following chemicalformula:

wherein

includes a carbon chain including a carbon number between 1 and 10,wherein R3 includes at least one selected from the group consisting of—S—, —P—, —P(O₂)—, —C(═O)S—, —C(═O)O—, —O—, —N—, —C(═O)N—, —SO₂O—,—SO₂S—, —SO—, and —SO₂—, and wherein R4 includes a tertiary carbon. 19.The method of claim 18, further comprising: during the exposing thelayer to the radiation beam, R4 of the protecting group leaves theprotecting group.
 20. The method of claim 15, wherein the forming thelayer including the metal additive component and the floating additivecomponent over the semiconductor substrate includes performing a dopingprocess to form the metal additive component in the layer.